Leading inhibition to neural oscillation is important for time-domain processing in the auditory midbrain
Leading inhibition to neural oscillation is important for time-domain processing in the auditory midbrain
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DOI：
10.1152/jn.00056.2005
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发表时间：
2005-07-01
影响因子：
2.5
通讯作者：
Feng, AS
中科院分区：
文献类型：
--
作者：
Galazyuk, AV;Lin, WY;Feng, AS
许多中枢听觉神经元表现出反常潜伏期移位（PLS），这是一种在较高声级下反应潜伏期较长的反应。PLS神经元被认为在回声定位蝙蝠发出调频声音的目标测距中发挥作用。我们最近报道，早期抑制单位的振荡放电是关键的PLS在下丘（IC）的小棕蝙蝠。本研究的目的是确定在回声定位蝙蝠和非回声定位动物（青蛙）：1）PLS的详细特征，以及PLS是否依赖于声级，频率和持续时间; 2）的时间过程中的抑制PLS使用成对脉冲范例。我们发现，22%的蝙蝠和15%的青蛙IC神经元表现出周期性的放电模式，在高声音水平的音调脉冲。发射周期是单位的具体和独立的声级和持续时间。其他IC神经元（蝙蝠28%;青蛙14%）表现出PLS。这些PLS神经元有几个共同的反应特征：1）PLS在很大程度上不依赖于声音频率和2）在第一个尖峰潜伏期的移位幅度是持续时间依赖性或持续时间容忍。对于PLS神经元，荷包牡丹碱的应用废除了PLS，并揭露了作为PLS构建块的单元的周期性放电模式。在成对的声音脉冲，PLS神经元表现出延迟依赖的反应抑制，证实高阈值的领先抑制负责PLS。结果还揭示了PLS的兴奋性和抑制性输入的时间及其在时域处理中的作用。
A number of central auditory neurons exhibit paradoxical latency shift (PLS), a response characterized by longer response latencies at higher sound levels. PLS neurons are known to play a role in target ranging for echolocating bats that emit frequency-modulated sounds. We recently reported that early inhibition of unit's oscillatory discharges is critical for PLS in the inferior colliculus (IC) of little brown bats. The goal of this study was to determine in echolocating bats and in nonecholocating animals (frogs): 1) the detailed characteristics of PLS and whether PLS was dependent on sound level, frequency, and duration; 2) the time course of inhibition underlying PLS using a paired-pulse paradigm. We found that 22% of IC neurons in bats and 15% in frogs exhibited periodic discharge patterns in response to tone pulses at high sound levels. The firing periodicity was unit specific and independent of sound level and duration. Other IC neurons (28% in bats; 14% in frogs) exhibited PLS. These PLS neurons shared several response characteristics: 1) PLS was largely independent of sound frequency and 2) the magnitude of shift in first-spike latency was either duration dependent or duration tolerant. For PLS neurons, application of bicuculline abolished PLS and unmasked the unit's periodical firing pattern that served as the building block for PLS. In response to paired sound pulses, PLS neurons exhibited delay-dependent response suppression, confirming that high-threshold leading inhibition was responsible for PLS. Results also revealed the timing of excitatory and inhibitory inputs underlying PLS and its role in time-domain processing.